Control apparatus



s- 9 3 E. A. KEELER 2,326,465

CON'IROL APPARATUS Filed Aug. 2, 1940 FIG. 2.

FIG. l.

- INVENTOR.

EARL A. KEELER ATTORN5Y.

PIIISI becsuse oi' tha chanzo in the division oi thc voitage across the resistance. inducta.noa und eapucitsnce 01 I:he rea.ctive circuit upon chv.nca in i'mquency o! the enerzizinz current saures. 'lhat is im ssy. ai: one ireqnency I:ho reactlve circuit presents a ziven impedance I:o I'.he iiow 01 current thereizhrough und the volta.ge is divlded in oue manner acrosa I:he resistance. inductance und ca.pacitance whereas at another irequency I:he Impedance presented hy said reacl:lve circuit in u. diiierent va.iue und I.he voitaze is divided in a difierent manner a.cross the resistance. inducizance und capacitance. When f.he resistance, inductance und capacita.nce mmprising I.he reactive circuit are properly chosen with respect 120 euch other a.nd with res pect 120 charactezistics 01 the components oi the coustnni: potential tmnstormer, II: ha.s been found that the Iendenny o! the voltage across the capacita.nce 110 increase with increase o! Irequency o: I;o decrease with decrease of frequency may be substantially eliminatecl.

l'ho variou.s ieatures 01' novelty which chancterize my invention are pointed out with particula.rity in the claims annexed to und I'orxn1n8 s. part. 01 this speciflcation. Fax s. heiter understa.nding o! the invention, however. its admtagea und speciflc objects attained with Its use. reierence should be had to the accompanying drawing und descriptive matter in which I have iliustrated a preierred embodixnent o! I;he Invention.

F1g. 1 in a. diasra.mxnatic Illustration 01 the wiring arrangement utilizing the oonstruction sbown in Fig. 2 und also Illustrtes the cnnecti0n o1 t.he series connecized inductance und ca.pucita.nce comprising the reactive clrcuit ior compensating I0: frequency varia.tions o! the energizing current souroe in accordance with my invention; und

Fix. 2 is a sectionai view o1 oue !orm 01 nonstrmztion o1 a. constant potential transiormer type regulator with which my Invention may be utiiized In Fig. 1 oi I;he drawina, I have illustrated more or lass diagramatica.lly the use o! the Improved voltage reguiator ot my invention in maintainins a eonstant direct current potentia.l acrass a pohentiometer sliciewi.re I. A variable portion o! I:he voltage aros,s the sliclewire I is opposed to the voltage developed by a. thermocoupie I which is inserted In a turmwe I or other computmsnt. ti:ue temperature 01 which II: is desired I;o ascertain. Diiiereneea in the volta.se developed by Ihn thermocouple 2 a.nd I.he portion oi I.ha alldewire volta.ge opposed thereto am detected by a sensitive Voltmeter or galvanometer I which mit! be o! I;he suspension or other suitable type. The portion o! the voltage acxoss the slidewire I 09- posed to the thermocouple voltae is axijustable by siiding a contact 5 along the .slidewlre. II. will be apparent such adjustmeni: 01 I:he oo1gtact I a.lnng the slidewire I ma.y be etlected automatica.lly in an: weil known manne: in response Iao the deflectiou of the mova.ble element or pointer oi the ga.iva.nometer l, bui; tor convenience and in order not to contuse I:he drawing, I have iliustrated the contact 5 a.s manually adjustable along the alidewire l by manipulation o! a hmob I.

In Fix. 2 I hure illustrated a. sectlonal view 01 a. weil known shell type oi volta8e compensatlnz transiormer which is seid commercially by the 801a Electric Compuny ot Chicago. Illinoia. 'ihin transfotmer in diaclooad in Iziua Sola pnbant roten-ad to hereinbetore.

As illustrated I:hn voltage compenmting transiormer compriaea two closed magnetic circuiias I und I. a. oentral core bar I which mn.y be ma.de up o! I-shaped laminations. the sidea o! which are in abutting contact with the end les II o! E- shaped ln.minationa II und the end lege I I o! E-shaped laminati0ns II. l'ho I-shnped und E- ahaped laminations am claxnped in operative rolation by any sultable means.

A prima.ry winding II in mounted on I:ho lefl: end o1 the core bar I. a.s seen in i.he drnwinc. For convenience Izhis end 01 the core bar has been designated the end portion II. 'I'he terminnia 01 the primary winding II are c0nneched to t.he supply conductors L und 1.:. the;' voltase und frequency o1 which are variable. Another winding II is mountecl on the risht end portion oi' Izhe core bar I which portion has been designated by the reierenee numeral I'l. 'I'he windlng II i.s spaced from the winding II but is magnetically coupled loosely therewith. As shown in Fix. 1. a condenser II in connected across ttue terminals of I;he winding II. Another winding II 18 positioned over I:he winding II und ia magneticaily coupled therewith. Pne terminnl III 01' the winding I9 comprises one bermlnal 015 the output circuit of I:he transiormer. Axiother winding II is mounted an I:he end portion II 01 I:h(e coro bar I. The wind.ing 21 is positioned over und in manetica.lly coupled tizhtly with the winding II. A conductor 22 oonnecta the right end termina.l oi' the winding 2I I:o the other term1nn.l oi the winding II. 'Ihe windings II und 2I therei'ore. am connected In series with the output circu.it 01 the transtormer, the oonductor III as mentioned hereinbefore comprising one output conductor o! the transtormer und a conductor II comprising another output conductor oi' the transiormer. An illustrated a. portion 01 I:he turna oi' the windina 2I are shunted by a. resistam:e 24 along which a conta.ct 25 Is adpted to bedjusted by manipulation o1. a Imob II. The conducbor II is nonnected to I;he oontact II. With this arranzement the eflective portion cf the wixiding II in seriea with the winding II may be readfly Husted an desired. 'Ihis is an important ieature oi' my pruent invention since by iacilitatim thil Wustment it is possible to eitect mach closer compenstion tor voita8e vuiationa o! tha alternatlnz au pply conducbors L und U. While the resistance 21 has been ahown oonnected in shunt with a. portion only 01 the winding 2I II: will be underaizood I;hat seid resistanoe may be connected in shunt I1o Ishe whole ot the winding II i! desire L 'I'he closed maznetlc circuits descrihed am euch provided wlth a high lealmge reactamoe path between the windlm II und II an the end poz1sion/ II an the one band und the windings II am! II on the end portion I'l oi' said core bar an the other band. A3 illustrated in the drnwinzs. auch high leakage reactance path coxnprises the cantra.l legs 21 and II o1 the respective E-sha.ped laminations II am! II. 'I'he leg; II und II terxninate short oi iahe adjncent sides o1 Ihn core bar I und thereby provide air zaps II und III between the iegs 21 und II und I:he core bar I.

'Ihe principie 01 operation oi the voltage regulating trans'iormer shown in Fix. 2 und shown by the dotted paart o! l"ig. 1 in cler1y sei; iorth in the ai'orementioned 8010 Patent 2.143545 und. thereiore, will not be eiaborated on herein. I"or the purposes o1 the present lnventlon, lt. l.s believed sufllclent to note that the llux sei: up by am hrlns a voltage across the prlmm wlndlns I5 will link wlth the. wlndlna I am! cause a definite reactance 00 be sei; up b:r the latter. As the voltage an the prlmarrwlndln II Is increased from zero 120 a hlgher level, the flux passlng throush the wlnding II I:ends to lncrease in nearly dlrect proportion I:o the prlmary flux because o1 the relucta.nce caused by the alr ganz 29 und 30. a. very Sll'lll amounl: 01 flux leaklng through the legs 21 und 20. As the voltage Induoed in the wlndlng I6 incteases. a critlcal polnt ls reached where resonance takes place. Under thls resonant; condltlon a definite amount of current flows thmugh the windin8 I6 and the condenser I0, whlch current will be llmited by the constants of the wlndinc III and the candenser I0 with the result that a substantially constant potential will be sei; up across the windlng I6, ss explained herelnnfter. und a corresponding amount o! magnetic flux will be set up In the end portion I'l of the core bar 8.

By virtue of the inherenl; characteristic cf a resonant circuit that lts power vector ma.y be many t1mes greater than that. of the generator which supplies the energy to the resonant circu.lt the change in flux densit? in section I0 of the core bar 9 due to variatlons in the voltage ot' the supply conductors L und L will ha.ve no appreclable eflect on the resonant circuit as lang as the magnetic denslty o! the sectlon II o! the core bar rema.ins under the maximum density o! section I1 of the core bar. Thls efiect ls obtained since the reluctance o1 the leakage pa.th through the legs 21 a.nd 20 i.s laben less than the reluctance o1 the sectlon Il cf the core bar whereby flux will leak through said leakage pa.th between the prlmary und resonant core portions.

Because 015 this leakage relucta.nce path the coefflcient of coupllng between the primary windlng I5 and the resonant circuit lncluding windlng I6 und condenser I0 .'is reduced to a. certaln optlmum value, thereby malntainlng a balanced condltion, so that the resonanb circult will continue to oscillate with the maximum eurrent therein a.t a. frequency equal to the frequency lmpressed on the pl'lmary windlng. With this sta.te of resona.nce obtalned. the wlndlng I0 will sei; up a magnetic fleld in the core sectlon I'I whlch will rema.in practlcally constant so lang as the density in the magnetic field o! the core portion II remalns at a lower denslty than thai: o1 the core portlon I'I. Thls substantially constant flow of flux in the core portlon I1 operates I;o produce a. substantlally consta.nt vollaage across the terminals of winding I0 am! cum denser I0, whlch voltage will remain practlcally constant irrespective of varlatlons in the voltage applled to the termlnals o1 the prlmary winding I5.

The resonant circuit including wlndlng I0 und condenser I8 therefore provldes a. consta.nt primary source cf volta.ge f01' the wlndlng I8. '.'flze output; voltage o1 the winding I0 will therefore have a. practically constant voltage level Independent of the voltage varla.flons In the primary winding I 5 so lang as the circuit lncluding windlng I6 und the cunrlenser III re1nain in resonance.

The winding 2I is coupled to the portlon I4 of the core bar 9 so thaI: upon varlation in the voltage applled 110 the term.inals 01 the wlnding I5, corresponding variations in the voltage acro'ss the terminals of the winding 2I am produced. Tha.t ls to say, the voltage lnduced in the windin: 2I will always be proportional 00 the turns ratio 02 prlmary windlng I0 anal wlndlng 2I.

An extremely constant level o! voltage may he malntained between the output conductors 20 and 23 cf the. voltage regulatlng transformer by sult.ably apportionlng the number 01 eflectlve turns on the wlnding 2I in relation to the number o! turns an the winding III. O2, if deslred. a.ny percentage of regulatlon o1 output voltage in relatlon I;o varlations ot the voltage of the alternatlng supply conductors L und U ma.y be obtained at the conductors 20 am! 23 by properly arranging or proportioning wlnding 2I in relatlon to the wlndlng I9. Foxexa.mple, if desired lt ls posslble I;o produce a decrease in the volta.ge between the conductors 20 and 23 upon an increase in the voltase. o! the supply conductors L a.nd L. 'Ihe provision 01' the resista.nce 20 und slldable contact 25 greatly facllitates auch apportionlng of the eflective turns cf wincllng '2I eonnected In circult wlth the wlndlng I9. I

rega.rd the provlslon o! the reslstance 20 und adJustable contact 25 as an important ieature 01 my present lnvention, since by lt.s use the need for careful wlnding of the preclse number of turns an the windlng 2I is eliminated thereby effecting a substantial reductlon in the cost of constructin the transformer.

I'he operation of the voltage regulatlng transformer descrlbed has so far been upon the assumptlon that the output conductors 20 anal 23 a.re open clrculted. that ls to say. are not cannected to a load clrcult. II a. load is connected I:o the conductors 20 and 23. however, a magnetlc flux will be developed in the resonant circuit lncludlng the conductor IG and condenser I0. whlch magnetlc flux will correspond to the load connected to the conductors 20 and 23. This operates to unbalance the magnetic flux in section Il o1 the core. 'I'his change in magnetlc flux In the portion I'I of the core, in turn, aflects the stable relation of the flux in the core sections H and I'I andalso the leakage rea.ctance through the shunt paths 21 and 28 und thereby causes more useful flux from the core section II I;o pass throush the core sectlon I I, which change in flux through the core I1 compensates for the energy used by the load circult a.nd at: the sa.me tlme ma.intalns the resonant circult in the deslred osclllatlng condltlon.

The operatlon of the voltage regulating apparatus described so far l'las been upon the assumpt1on that the frequency of the alternating Voltage of the supply conductors ls constant. Upon variation in sald frequency, howaver, the inductiva reactance of the wlndlngs I5, I5 III and 2I of the voltage regulatlng transformer is varlecl correspondingly und as a. result the magnetic flux in .sectlon I'l cf the core bar 9 ls varied. Thls change In flux through section I'I atfects the stable relatlon of the flux in the core sectlon I'I and I0 anal, unless compensatecl (er, would result in the establlshment of a. dllferent voltage between the output conductors 20 and 23 o1 the voltage regulatlng transformer. Thus, cl:anges in frequency of the alternating voltage cf supply conductors L und L tend to produce er:ror in the output voltage cf the voltage compensated transformer.

In acoordance wlth xny present lnvention such varlatlons in output voltage of the voltaga regulatlng transformer upon va.rlatlon in the frequency cf the altematlng supply conductors L and L are corrected or compensatecl for by interposing a. reactlve circult between the output couduciaor; o1 the rezulatin: 'lillllf0l'lllel und the lau! device. As illustrated thia ructive cimuii; lncludes an ad.lustable ruista.nce l, an inductance II und a capacitance 38 which are connected in mies between the output wnducizora 20 und II oi the transiormer. 'I'he resista.nce Il ma.y be adjusted by manipulation oi' a knob N. 'I'he terminals ai the capacitance are connected tao the terminals o1 -the load devlce an which lt; is desired ta maintain a, constant Potential.

'I'he serles aonnected resistance 8l. inductnnce 82 und candenser 38 may be recarded an a frequency responsive circuli: which operates i:o vnry the load an the autput circuit 01 the voltue regulating transformer upon varlation in frequency oi' the alternating aupply conductora 1.. und l.?. By praperly proportionin: realstanae 8l inducb ancc 32 am! capacltance II, the 1oa.d an the autput circuit a! the voltlge rezulu.izlnz transiormer in automatically varied im als least partly compansate rar the eflect pradueed in the transiarmer by the cha.nge in irequency of the impressed albematlng voltsge. Thai'. i; 1:0 say. the denslty change pro cluced in the core secision l'l as a. resuli; 01 the change in frequency o1 the altematin: voltage supply candixctors I. und L is ai: least partly correctecl or compensated tor by the change in load an the autput circuit a! the transiorxner praduced by the series connected resistance II. inductance 82 anti c&pacltance 'I'he remaincler o! the compensaisian needed to evercome the ei!ect o1 the change in irequency oi. the alternating supply conductors L und L is believed to be abtained as'a. result o1 the change in dlvisian of the voltage across the elements 3l 32 und 31 o! the reactive circuiiz. Theta ls to ss.y at one irequency 01 the voltage o! the supply concluctors, the autput voltage 01 the transi'onner will be dlvided in ane manner a.cross the elements II, 32 und 33 oi' the reactlve circuit, und as said trequency cha.nges the divislon af the transtarxner oui:put valtage acrasssaid elementa 3l 32 und 33 is crrespandingly varied. These twa compensating eflects combine ba produce the precise amount af campenaatlon requireci to neutralize the eflect oi' the line valizage irequency change an the voltage across the termlnals 01 capacitar 83. By way o! Illustration, when the voltage compensatlng transformer embraaed by the doiated lines in Flg. 1 is a "SolaCompensated Transformer ha.ving the following rating:

Primary volts-95-l25 a.i: 60 cycles/sec. Becandax? volts20:tl% with an oui;put of 10 valt-amperes.

the voltaae mcross the bermlnals o! the candenser 33 may be malntained consizant i:o wlthin onehali of ane percent varia.tion upon an increa.se in line voltage iram 95 volts ta 125 volts nnd with a. trequency shiti; 01 iram 54 cycles per seaoncl to 68 cycles per second when the resistance o! the resistance 3l is 50 ohms. the inductarme ot' the inductance 32 is 0.75 Henry at 0.5 M. A.. the D. C. resistance oi' lnductance 52 being 30 ohms, am! the capacitance o1 the candenser 33 is 30.5 microtarads. Under these candltions, I have determlned that the voltage between the conductors und 23 in 19 volts und the volisage across the terminals ai the condenser 33 is 9.8 volts.

In the form o! my inventlon disclosed in Flg. 1, the voltage across the terminals 01 the candenser 33 is applied to the termina.ls o! a. iull wa.ve rectlfler 55 which ma.y be a! the copper axide o1 other suitable type und the output termlnl.ls with tha latter are connectad thloWh an adlusta.ble reslstance I5 i;o the tfll'llllillll' o! the alldewlro reaiatanae I.

Whila I have illustratecl the use o! xny inven- 5 tian tor maintaininz a conatant valtage across a potentidmete: slidewire uaed f0l. measurlng the volta.ge developed bar a thermoeouple, lt will be understoad that my inventlon is not limited to auch use but tha.t it im: numerous other advantageous uns.

While in accardance wlth the provlsions 01 the statutes. I have illustrated and deacribed the besi: kann af my lnvention now lmown izo me, it will be appareni; ta thase skllled in the a.rt that changes may be milde in the torm o! the apparatus disclosed wlthouis departing traxn the spirii; a1 my inventlon as sei: tarth in the appencled claims. und lahmt in seine cases cerlaain ieatures o! my invention may sometlmes be used i;o advantase withaut a. corresponcllng use cf oi:her features.

Havlmz naw deacribed my lnvention, whai: I claim a: new und deaire to secure by Letters Patent 1s:

l. Contral apparatus comprising the combinatian 91 a, magnetic eure. a. windlng an said eure adapted ta be connected to source o! fluctuauing voltnge. a second winding an said core in spmced relatlan i;a ss.ld flrsi: mentioned winding, a reaci:ive clrcuit including resist.ive inductive und. capaciizive aomponents, a. third winding an sald core in inductive relation to the firsi: mentioned winclins a.nd connected in seriea with said second mentioned wincling and sald reactive cir- 35 cult, an autput clrcult connected acrosa the ca.-

pacii:ive component 01 said reactlve clrcu.it sald core pravldinz a. hish lenkage reactance path tor a. pori;ian 01 the flux ta thread through sa.id i'irst und third wlndings i:o the exclusion 01 said second 40 winding, a resonant circuit includinz a. comlenser anal a. taurth winding. the resonani: circuit operai:lng a.t a frequency substantially equal to the irequency 01 said aource. the fouxth winding aein: in lnductive relation 1:0 the secand wlncling, and means bo adjust the relative eflectlve partians o! sald seeond and third windinss which are connected in sattes.

2. 'I'he comblnation 01 alaim 1 wherein the last mentloned means comprlses a resistance Conneci;ed in shunt to sald third winding und a, cantact adiusbable along the lengish o1 said resistance.

3. Contral apparatus comprlsing the comblnatian oi! a magnetic core s, windlng an said eure adapised to be connecbed to a source ai' fluctuatin: voltage. a second wlndlng an said eure, sa.id core providing a high leakage reactance path i'or a. portlon 01 the flux to thread thmugh one o! the windinss ta the exclusion 01 the other wlnding, a. reactive circuit including resistive. induct.ive und capacltive companents connected cross the terminals o! said second winding an autput circult connected across the ca.pacitlve camponent a1 said reactive circult, am! means rar ma.intaining the potentlal across sa.id output circuit substantially constant irrespective o! fluctuations in the voltase oi' saicl source camprising a resonant circuii: includins a candenser and. a third winding. the resona.nt circuli: aperating a.t a trequency aubstantlnlly equal 120 the trequenay 01 the voltage impressed an the iirst mentianed wlnding, the thlrd winding belng in inductlve relation to seid secand winding.

4. Contral appamtus comprlslng the combina- 75 tion 01 a maznetic eure, a. windlng an sa.id core adapted to be connected to a. source o1 fluctuat- Ing voltage an output circult, a second wlnding on said core adapted to be connected to said output circu1t, a third winding an sald eure, sa1d core providing a high leakage pa.th for a portion cf the flux to thread through one of the windings 1:0 the exclusion of t.he other windlng, means for maintaim'ng the potentlal across the output circuit substantially constant irrespective 015 fluctuations in said source 01 voltage comprising a resonant circuit including said third wlnding and a condenser, the rescnant circuit operating a1: a frequency substantially equal to the frequency cf the voltage impressed on the flrst winding, and means for maintaining the potential across the outxnut circuit substantlaliy constant lrrespective of variations of frequency cf said source cf voltage including a. condenser and an inductance connected across sald second winding, the output circuit being connected across sa.id last mentioned condenser.

5. Control apparatus including in coxnblnation a. constant potential transtormer having an lnput circuit am! an output clrcuit, a. source 01' fluctuating voltage connected to the lnput circuit o1 said transtormer, said transtormer being characterized by the fach that lt operates to maintain the volta.ge across its output clrcuit substantially constant irrespective o! fluctuations in the voltage o1 said sour9e a. load circult counected to the output circuit of said transformer, und means for maintaining the potential across said load circuit substantially constant irrespective of fluctuatlons in the frequency 013 said source comprising a react1ve circuit interposed between said loa.cl circuit a.nd the output circuit of said transformer.

6. 'I'he combination of claim 5 wherein the rea0t1ve circuit includes resistive, capacltive and lnductlve components, am! the load circuit ls EARL A. KEELER. 

